Dates

I've created a date field called 'COSHH Review Date'. During a Job Queue there is a check against this field to see if the date is within 30 days in the future of the current Work date.
In my current code however it is saying a value is within this range even though it may be months ahead of the Work date. How can this be am mended to only continue if it is within 30 days?

Parameter Value 1 = 30.

IF recItem.FINDSET(FALSE, FALSE) THEN REPEAT
IF (recItem."Coshh Review Date" < WORKDATE) AND
(recItem."Coshh Review Date" >= CALCDATE('<-' + recJobQueueEntry."Parameter Value 1" + 'D>', WORKDATE) ) THEN BEGIN